Photographic color processes and compositions



June 19, 1962 H. G. ROGERS ETAL 3,039,869

PHOTOGRAPHIC COLOR PROCESSES AND COMPOSITIONS Filed April 24, 1957 Supporl' {12 Silver Halide Emulsion Layer Layer of Processing Composilion l6 Con'l aining a Dye Developer, a Firsl' [8 20 Developing Agen'l' and a Second Developing Agen'l' I Image-Receiving Layer Image -Fleceiving Layer suppr+ Rupl'urable Con+ainer Holding Processing Composi-l'ion Including a Firsl' Developing Agen'l' I and a Second Developing Agenl Blue-Sensil'ive Emulsion 42 Layer Conl'aining Yellow Dye Developer 40 Spacer Layer Green -Sensi+ive Emulsion Con'laining Magen'l'a Dye Developer Spacer Layer 6O 62 Red-Sensil'ive Emulsion 66 Layer Con'l'aining Cyan Dye Developer FIG. 2 SWIM @igfv ATTOR N YS United States Patent ()ffice 3,939,869 Patented June 19, 1962 3,039,869 PHQTQGRAPHIC COLOR PROCESSES AND COMTGSITIONS Howard G. Rogers, Weston, and Harriet W. Lutes, Boston, Mass, assignors to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed Apr. 24, 1957, Ser. No. 654,781 36 Claims. (Cl. 96-3) This invention relates to photography and, more particularly, to improvements in photographic difiusion-transfer reversal processes for obtaining color images utilizing dye developers.

The copending application of Howard G. Rogers, Serial No. 415,073, filed March 9, 1954, now abandoned in favor of a continuation-in-part thereof, Serial No. 748,421, filed luly 14, 1958, now U.S. Patent 2,983,606, granted May 9, 1961, discloses and claims diffusion-transfer reversal processes wherein dye developers are utilized to develop the latent image present in an exposed photosensitive emulsion, and a positive color image is imparted to a superposed image-receiving layer by unreacted dye developer originating from unexposed areas of the exposed photosensitive emulsion. The dye developers of this process are dyes which contain, in the same molecule, a silver halide developing function and a chromophoric system of a dye. A particularly useful class of dye developers are those containing a hydroquinonyl developing function.

Diffusion-transfer reversal processes utilizing dye developers are improved by the use, in conjunction with the dye developer, of a S-pyrazolidone developing agent as disclosed and claimed in the copending application of Howard G. Rogers, Serial No. 518,979, filed June 29, 1955, now abandoned in favor of a continuation-in-part thereof, Serial No. 748,421, filed July 14, 1958.

We have now discovered that diffusion-transfer reversal processes utilizing dye developers may be substantially improved by the utilization, in conjunction with a dye developer and a 3-pyrazolidone developing agent, of another or second silver halide developing agent.

It is a primary object of this invention to provide novel photographic processes, products and compositions whereby improved control of the transfer of unoxidized dye developer to an image-receiving layer may be obtained.

A further object of this invention is to provide novel photographic processes, products and compositions whereby the quality of the positive image, particularly the highlights and light steps obtained in difiusion-transfer reversal processes utilizing dye developers, may be improved.

Another object of this invention is to provide novel photographic processes, products and compositions whereby increased density and improved contrast may be obtained in color diffusion-transfer reversal processes employing dye developers.

A further object of this invention is to provide photographic processes, products and compositions for use in multicolor diflusion-transfer reversal processes utilizing I dye developers whereby improved color separation may Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a diagrammatic cross-sectional view of one embodiment of this invention during processing; and

FIG. 2 is a diagrammatic cross-sectional view of one embodiment of a photographic product for use in accordance with this invention and comprising a multilayer photosensitive element, an image-receiving element and a rupturable container holding a processing composition.

As stated above, it has been proposed to form color images by a diffusion-transfer reversal process by the use of a dye developer. In processes of this type, a photosensitive element containing a silver halide emulsion is exposed and wetted by a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark and the exposed photosensitive element is superposed prior to, during, or after wetting, on a sheetlike support element which may be utilized as an imagereceiving element. In a preferred embodiment, the photosensitive element contains a layer of dye developer and the liquid processing composition is applied to the photosensitive element in a uniform layer as the photosensitive element is brought into superposed relationship with an image-receiving element. It is also contemplated to utilize the dye developer in the liquid processing composition where monochromatic images are desired. The liquid processing composition permeates the emulsion to initiate development of the latent image contained therein. The dye developer is immobilized or precipitated in exposed areas as a consequence of the development of the latent image. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation and especially as regards its solubility in alkaline solutions. It may also be due in part to a tanning eiiect on the emulsion by the oxidized developing agent. In unexposed and partially exposed areas of the emulsion, the dye developer is unreacted and diffusible, and thus provides an imagewise distribution of unoxidized dye developer, dissolved in the liquid processing composition, as a function of the point-to-point degree of exposure of the silver halide emulsion. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer or element, said transfer substantially excluding oxidized dye developer. Under certain circumstances, the layer of the liquid processing composition may be utilized as the image-receiving layer. The image-receiving element receives a depthwise diflusion, from the developed emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive color image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. If the color of the transferred dye' developer is afiected by changes in the pH of the imagereceiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. The desired positive image is revealed by stripping the image-receiving element from the photo-' sensitive element at the end of the imbibition period.

We have now discovered that diifusionatransfer reversal processes utilizing dye developers may be substantially improved by the use, in conjunction with the dye developer, of a S-pyrazolidone developing agent, which may be referred to as a first developing agent, and at least one additional developing agent, which additional developing agent may be referred to as a second developing agent. The use of such a combination of developing agents provides color transfer images of improved density, contrast, highlight rendition and, in the case'of multicolor images, improved color separation. We have found that such a combination of developing agents provides images of superior quality as compared with images obtained by the use of a dye developer with only one developing agent whether such other developing agent is a 3-pyrazolidone developing agent or a second developing agent as set forth hereinafter. I

Dye developers, as noted above, are compounds which contain in the same molecule both the chromophoric system of 'a dye and also a silver halide developing function. By a silver halide developing function is meant a grouping adapted to develop exposed silver halide. A preferred silver halide developing function is a hydroquinonyl group. Other suitable developing functions include o-dihydroxyphenyl and oand p-amino-substituted hydroxyphenyl groups. In general the developing function includes a benzenoid developing function. Examples of representative dye developers are given in the previously mentioned application of Howard G. Rogers, Serial No. 415,073. Additional useful dye developers are described in the following copending applications:

Application Serial No. 449,514, filed August 12, 1954,

in the names of Elkan R. Blout and Myron S. Simon.

' Application Serial No. 450,208, filed August 16, 1954, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green and Myron S. Simon.

Application Serial No. 471,542, filed November 26, 1954, in the names of Ellran R. Blout, Saul G. Cohen, Milton Green, Howard G. Rogers, Myron S. Simon and Robert B. Woodward.

Application Serial No. 478,922, filed December 30, 1954, in the names of Elkan R. Blout, Marilyn R. Cohler, Milton Green, Myron S. Simon and Robert B. Woodward.

Application Serial No. 612,045, filed September 25, 1956, in the names of Elkan R. Blout, Milton Green and Howard G. Rogers.

Application Serial No. 612,052, filed September 25, 1956, in the names of Milton Green and Howard G. Rogers.

Application Serial No. 612,053, filed September 25, 1956, in the name of Myron S. Simon.

Application Serial No. 612,054, filed September 25, 1956, in the names of Helen P. I-Iusek and Myron S. Simon.

Application Serial No. 612,055, filed September 25, 1956, in the name of Helen P. Husek.

As previously stated, the first developing agent used in combination with a dye developer is a 3-pyrazolidone developing agent. Developing agents of this class may be represented by the formula:

in which R R R R and R each represents substituents such as hydrogen, aryl or alkyl groups, including substituted alkyl and aryl groups. The alkyl groups preferably contain from 1 to 4 carbon atoms, inclusive. A large number of developing agents within this class are reported in the literature; see, for example, US. Patent No. 2,289,- 367, issued July 14, 1942, to John David Kendall, and US. Patent No. 2,731,300, issued June 19, 1956, to

Thomas H. James et al. A particularly useful developing agent of this class is l-phenyl-3-pyrazolidone, which is commercially available under the trademark Phenidone from Ilford, Ltd.

The second developing agent utilized in combination with the dye developer may be described broadly as a benzenoid developing agent. In general, developing agents of this class contain an aryl nucleus substituted in the ortho or para positions, with respect to each other, by hydroxyl and/or amino groups, including substituted amino groups, and this nucleus also may have other nuclear substituents, e.g., alkyl, aryl, arylthio, etc. As examples of suitable developing agents within this group, mention may be made of the following:

(1 2,4-diaminophenol (2) Toluhydroquinone (3 2,5 bis-ethyleneimino-hydroquinone (4) p-Benzylaminophenol (5 p-Anilinophenol 6) Xylohydroquinone (7) p-Toluthio-hydroquinone (8) 2-amino-4-phenyl-phenol (9) 5 ,8-dihydro-1,4-naphthohydroquinene l0) o-T oluthio-hydroquinone 11) 5 ,6,7,8-tetrahyd.ro- 1,4-naphthohydroquinone 12) 2-methoxy-4-aminophenol 13) Phenylhydroquinone 14) p-Aminophenylhydroquinone 15) 4-amino-3-ethylphenol 16) 4-amino-3,S-dimethylphenol 17) 4-amin0-2,3-dimethylphenol l8) 4- amino-2,S-dimethylphenol 19) 6-aminothymol (20) Thymolhydroquinone (21 2,6-dimethylhydroquinone In accordance with this invention, it is contemplated to utilize, in combination with a dye developer, at first developing agent and at least one second developing agent in both monochromatic and multicolor diffusion-transfer reversal processes. Monochromatic images may be obtained in accordance with the technique above described wherein the dy developer may be in or behind the silver halide emulsion, or in the processing composition.

FIG. 1 of the accompanying drawing illustrates one method of processing a silver halide emulsion to obtain a monochromatic transfer image in accordance with this invention. An exposed photosensitive element 10 comprising a support 12 and a silver halide emulsion 14 is processed with a processing composition 16 while in superposed relationship with an image-receiving element 18 comprising a support 22 and an image-receiving layer 20.- As shown in the particular embodiment depicted in FIG. 1, the processing composition includes a dye developer, a first developing agent and a second developing agent. The processing composition permeates the silver halide emulsion layer 14 to provide a uniform distribution of dye developer therein. In exposed areas of the silver halide emulsion layer 14, the dye developer will be immobilized as a result of development of the latent image. In unexposed areas, the dye developer will remain mobile, due to its solubility in theprocessing composition, and thus provides an imagewise distribution of mobile dye developer available for transfer to the superposed'imagereceiving layer 20. The image-receiving element 18 is separated from its superposed relationship with the photosensitive element 10 after at least a portion of said imagewise distribution of dye developer has been transferred.

In lieu of utilizing the dye developer and the first and second developing agents in the processing composition, one or more of these reagents may be incorporated initially in the photosensitive element, e.g., in the silver halide emulsion or in a layer behind said emulsion.

It is also contemplated to utilize a film structure wherein the silver halide emulsion is coated over the image- Example 1 A photosensitive element is prepared in a manner similar to that set forth in Example 9 of the aforementioned copending application Serial No. 612,054. An imagereceiving layer of polyvinyl alcohol is applied over .a support, followed by a stripping layer and a silver halide emulsion layer. This photosensitive element is exposed and processed, in superposed relationship with a spreading sheet, with an aqueous composition comprising:

Percent Sodium carboxymethyl cellulose 4.5 Sodium hydroxide 4.0 Potassium bromide 0.2 Sodium Carbonate 4.0 1-phenyl-3-pyrazolidone 0.2 2,S-bis-ethyleneiminohydroquinone 0.3

5 amino 4 (2',5' dimethoxy 4' [p (2,5- dihydroxyphenyl) phenylazo] phenylazo lnaphthol 5.0

The image-receiving element is separated after a twominute imbibition period and washed briefly to remove any traces of the processing composition. The brownishblack positive image obtained is substantially better than that obtained under the same conditions using a similar processing composition which does not contain 2,5-bisethylene-imiuo-hydroquinone. The image has significantly greater density and contrast, as well as substantially cleaner highlights.

Multicolor images may be obtained using dye developers in diffusion-transfer reversal processes by several techniques. One such technique contemplates the use of a photosensitive silver halide stratum comprising at least two sets of selectively sensitized minute photosensitive elements arranged in the form of a photosensitive screen. Transfer processes of this type are disclosed in the aforementioned application of Howard G. Rogers, Serial No. 415,073 and also in the copending application of Edwin H. Land, Serial No. 448,441, filed August 9, 1954, now U.S. Patent 2,968,554 granted January 17, 1961. In such an embodiment, each of the minute photo sensitive elements has associated therewith an appropriate dye developer in or behind the silver halide emulsion portion. In general, a suitable photosensitive screen,

prepared in accordance with the disclosures of the lastmentioned copending applications, comprises minute redsensitized emulsion elements, minute green-sensitized emulsion elements and minute blue-sensitized emulsion elements arranged in side-by-side relationship in a screen pattern and having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. It will be understood that the first developing agent and the second developing agent contemplated in accordance with this invention may be incorporated in the respective photosensitive elements or in the processing composition,

Another process for obtaining multicolor transfer images utilizing dye developers employs an integral multilayer photosensitive element such as disclosed and claimed in the copending application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956, wherein at least two selectively sensitized photosensitive strata are superposed on a single support and are processed, simultaneously and without separation, with a single, common image-receiving layer. A suitable arrangement of thi type comprises a support carrying a redsensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. The dye developer may be utilized in the silver halide emulsion layer, e.g., in the form of particles, or it may be employed as a layer behind the appropriate silver halide emulsion strata. Each set of silver .halide emulsion and associated dye developer strata may be separated from the other sets by suitable spacer strata, for example, by a layer of gelatin or polyvinyl alcohol.

A multilayer photosensitive element of the type just mentioned is illustrated in FIG. 2 of the accompanying drawing. A support 66 carries a layer 64 containing a cyan dye developer; a layer 62 of a red-sensitive silver halide emulsion; a spacer layer 60, e.g., of gelatin or polyvinyl alcohol; a layer 58 containing a magenta dye developer; a layer 56 of a green-sensitive silver halide emulsion; a spacer layer 54; a layer 52 containing a yellow dye developer; and an outermost layer 50 of a bluesensitive silver halide emulsion. In certain instances, it

e may be desirable to incorporate a yellow filter in front of the green-sensitive emulsion layer, and such yellow filter may be incorporated in the spacer layer. Where the yellow dye developer is of the appropriate color and present in a state capable of functioning as a yellow filter, a separate yellow filter may be omitted.

Referring again to FIG. 2, the multilayer photosensitive element 46 is shown in spread-apart relationship (as, for example, during exposure) with an image-receiving element 40 having mounted thereon a rupturable container 48 holding a processing composition. The image-receiving element 4% comprises a support 42 and an imagereceiving layer 44. After exposure, the image-receiving element 40 is brought into superposed relationship with the multilayer photosensitive element 46 and the rupturable container 48 ruptured by application of suitable pressure, e.g., by advancing between a pair of rollers, not shown, and a layer of the liquid composition spread between the superposed elements. After a suitable imbibition period during which at least a portion of the dye developer associated with unexposed areas of each of said emulsions is transferred to the superposed image-receiving element, the latter element is separated to reveal the image. Although the first and second developing agents are contained in the rupturable container 48 in the embodiment shown in FIG. 2, it is to be understood that one or both of said first and second developing agents may be located initially in appropriate layers of the multilayer photosensitive element, e.g., in an emulsion layer and/ or in a layer containing a dye developer. contemplated to position a portion of one or both of said first and second developing agents in the photosensitive element (whether monochrome or multicolor), and to incorporate the balance thereof in the processing composition.

The improved results obtainable in multicolor diflusion transfer-reversal processes in accordance with this invention may be demonstrated by the following, illustrative example.

Example 2 An integral multilayer photosensitive element similar to that shown in FIG. 2 of the accompanying drawing is prepared in a manner similar to that described in Example 2 of the aforementioned copending application Serial No. 565,135. This photosensitive element com .prises the following layers, laid down in the order recited,

on a suitable support, e.g., a gelatin-coated film base:

(1) A layer of a cyan dye developer, i.e., l,4-bis-[B-(2',5'-

dihydroxyphenyl -propylarnino] -anthraquinone.

(2) A red-sensitive silver halide emulsion layer.

It is also The efiect of the addition of various developing agents may be tested using, as a basic processing composition, an aqueous solution comprising:

. Percent Sodium carboxymethylcellulose 4.5 Sodium hydroxide -i 3.0

to which is added an appropriate quantity of the developing agent to be tested. It will be understood, of course, that a processing composition may also contain small amounts'of other photographic reagents, e.g., preservatives, restrainers, etc.

In testing the elIect of each developing agent, the photosensitive element is exposed and then processed in superposed relationship With an image-receiving element comprising a layer of N-methoxymethyl polyhexamethylene a'dipamide (available from E. I. du Pont de Nemours & Co., Inc., Wilmington, Delaware, under the trade name Nylon Type F8) carried on a cellulose acetate-coated baryta paper. The image-receiving element is stripped apart from the photosensitive element at er an imbibition period of approximately six minutes.

A series of tests were performed in which the following quantities of developing agent were added to a standard processing composition similar to the above-mentioned basic processing composition.

7 Percent Test 1: l-phenyl-3-pyrazolidone 1.0 Test 2: 2,5-bis-ethyleneiminohydroquinone 1.0 Test 3: p-benzylaminophenoL", 1.0 Test 4:

l-phenyl-3-pyrazolidone 0.6 p-benzylaminophenol 0.4 Test 5:

l-phenyl-3-pyrazolidone 0.6 2,S-bis-ethyleneiminohydroquinone 0.4 Test 6:

l-phenyl-4,4-dimethyl-3-pyrazolidone 0.6

5,6,7,8 -tetrahydro-1,4-naphthohydroquinone- 0.2

A comparison of the positive multicolor transfer images obtained in the above tests shows that the images obtained in Tests 4 and 5 using a combination of developing agents, one of which is a 3-pyrazolidone developing agent, exhibited markedly superior color separation, increased density, improved blacks and grays, and cleaner highlights than the images obtained in Tests 1, 2 and 3 using the same developing agents separately. The positive image obtained in Test 6 also exhibits the abovementioned superior qualities as compared with images using only a 3-pyrazolidone developing agent.

It. will be noted that the quantity of developing agent added in Tests 1 through 5 was maintained at a constant 1%. This demonstrates that the improved results obtained are attributable to the use of a combination of developing agents and not to a variation in the quantity of developing agent present.

Although the above examples utilize a combination of one first developing agent and one second developing agent, it is also contemplated to employ a combination of developing agents including two or more of each of said classes of developing agents. An example of one such combination utilizes l-phenyl-3-pyrazolidone, toluhydroquinone and 2,4-diaminophenol.

A further technique for obtaining multicolor images employs a plurality of photosensitive elements associated with an appropriate number of image-receiving elements and adapted to be treated with one or more liquid processing compositions, the appropriate dye developers being incorporated in the photosensitized elements or in the liquid processing compositions. Examples of film structures of this type are disclosed in U.S. Patent No. 2,647,049 issued to Edwin H. Land.

The dye developers utilized in the processes of this invention may be incorporated in the photosensitive element, for example, in," on, or behind the silver halide emulsion, or they may be employed as a component of the liquid processing composition, or in the image-receiving element where monochromatic images are desired. The dye developer ispreferably in a coating or layer behind the'silver halide emulsion and such a layer of dye cvelop-er may be applied by the use of a coating solution containing about 0.5 to 8 percent by weight of the dye developer. Similar concentrations may be used if the dye developer is utilized as a component of the liquid processing composition. a

The first developing agent or 3-pyrazolidone developing agent and the second developing agent may be employed as components of the liquid processing composition. It is also contemplated to employ one or both of these developing agents in the layer containing the dye developer or in the silver halide emulsion. Thus, one may utilize one of these developing agents in the liquid processing composition and the other developing agent in the silver halide emulsion or in the layer containing the dye developer.

Particularly useful results have been obtained by the use of a quantity of first developing agent and second developing agent, combined, which provides approximately 25 to 125 developing units per developing units supplied by the dye developer(s). It will be understood that this ratio may be varied and still provide improved images. The total developing units thus available provide from 50 to 400% excess developing units, based on the units of developable silver halide present, the dye developer supplying at least a quantity of developing units equal to the units of developabie silver halide in fully exposed areas. It was particularly unobvious that the dye developer should be preferentially oxidized, and the control thereof so substantially improved, in a system containing such a large quantity of developing units supplied by developing agents other than the dye developer. It is believed that the preferential oxidation and resulting immobilization of the dye developer is a consequence of its having the least soluble oxidation product. It appears that the dye developer may be oxidized and immobilized as a result of a reaction, e.g., an energy transfer reaction, with the oxidation product of a developing unit provided by the first and second developing agents, the latter developing agents being oxidized by development of the exposed silver halide. Such a reaction of oxidized developing agent with unoxidized dye developer would regenerate the first or second developing agent for further reaction with exposed silver halide.

, The liquid processing composition herein referred to comprises at least an aqueous solution of an alkaline compound, for example, diethylamine, sodium hydroxide or sodium carbonate. As indicated above, the liquid processing composition may also contain the first developing agent or the second develop-ing agent, or both. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin uniform layer, it might also include a viscosity-increasing compound constituting film-forming material of the type which, when said composition is spread and dried, forms a relatively firm and relatively stable film. A preferred film-forming material is a high molecular Weight polymer such as a polymeric, Water-soluble ether which is inert to an alkaline solution as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials or thickening agents Whose ability to increase viscosity is substantially unaffected if left in solution for along period of time may also be used. The film-forming material is preferably contained in the processing composition in suitable quantifies to impart to said composition a viscosity in excess of 1,000 centipoises at a temperature of approximately 24 C. and preferably of the order of 1,000 to 200,000 centipoises at said temperature. Illustrations of suitable liquid processing compositions may be found in the several patents and copending applications herein mentioned and also in examples hereinafter given. Under certain circumstances, it may be desirable to apply a liquid processing composition to the photosensitive element prior to exposure, in accordance with the technique described in the copending application of Edwin H. Land, Serial No. 498,672, filed April 1, 1955.

The dye developers are preferably selected for their ability to provide colors that are useful in carrying out subtractive color photography, i.e., cyan, magenta and yellow. It should be noted that it is within the scope of this invention to use mixtures of dye developers to obtain a desired color, e.g., black. Thus, it is to be understood that the expression color as used herein is intended to include the use of a plurality of colors to obtain black, as well as the use of a single black dye developer.

In all products employed in the practice of this invention it is preferable to expose from the emulsion side. It is, therefore, desirable to hold the photosensitive element and the image-receiving element together at one end thereof by suitable fastening means in such manner that the photosensitive element and the image-receiving element may be spread apart from their superposed processing position during exposure. A camera apparatus suitable for processing roll film of the type just mentioned is provided by the Polaroid Land Camera, sold by Polaroid Corporation, Cambridge, Massachusetts, or similar camera structure such, for example, as the camera forming the subject matter of US Patent No. 2,435,717. Camera apparatus of this type permits successive exposure of individual frames of the photosensitive element from the emulsion side thereof as well as ndividual processing of an exposed frame by bringing said exposed frame into superposed relation with a predetermined portion of the image-receiving element while drawing these portions of the film assembly between a pair of pressure rollers which rupture a container associated therewith and elfect the spreading of the processing liquid released by rupture of said container, between and in contact with the exposed photosensitive frame and the predetermined, registered area of the imagereceiving element.

The nature and construction of rupturable containers such as that shown in FIG. 2 is wellunderstood in the art; see, for example, US. Patent No. 2,543,181, issued to Edwin H. Land on February 27, 1951, and US. Patent No. 2,634,886, issued to Edwin H. Land on April 14, 1953.

The image-receiving element comprises an image-receiving layer of opaque or transparent material which is liquid permeable and dyeable from alkaline solutions and which has been illustrated for purposes of simplicity as comprising a single sheet of permeable material, for example, paper. This element, however, may comprise a support upon which at least one liquid-permeable and dyeable layer is mounted. The support layer may have a waterimpermeable subcoat over which the stratum of permeable and dyeable layer is applied. In certain instances, the dyeable layer may comprise a layer of liquid processing composition which is adapted to remain adhered to the support layer upon stripping.

' A preferred material for the image-receiving layer is a nylon and preferably a nylon such as N-methoxymethyl polyhexamethylene adipamide which is available under the trade name of Nylon Type F8 from E. I. du Pont de Nemours & Co. Other materials suitable for image-receiving layers comprise a partially hydrolyzed polyvinyl acetate such as that commercially available under the trade name of Vinylite MA-28-18 from Bakelite Division, Carbide and Carbon Chemicals Co.; polyvinyl alcohol with or without plasticizers; baryta paper, i.e., a support having a baryta coating thereon; cellulose acetate with filler as, for example, one-half cellulose acetate and onehalf oleic acid, and other materials of a similar nature, as is well known in the art.

While a rupturable container, such as container 48 in FIG. 2, provides a convenient means for spreading a liquid processing composition between layers of a film unit whereby to permit the processing to be carried out'within a camera apparatus, the practices of this invention may be otherwise effected. For example, a photosensitive element, after exposure in suitable apparatus and while preventing further exposure thereafter to actinic light, may be removed from such apparatus and permeated with the liquid processing composition as by coating the composition on said photosensitive element or otherwise wetting said element with the composition following which the permeated, exposed, photosensitive element, still without additional exposure to actinic light, is brought into contact with the image-receiving element for image formation in the manner heretofore described.

It is also to be understood that the invention may be successfully practiced without the use of a film-forming material in the liquid processing composition. As an illustration, a nonviscous liquid processing composition is particularly applicable with the processing technique last mentioned above and may be applied to the exposed photosensitive element by imbibition or coating practices and may be similarly applied to the image-receiving element before said elements are brought into superposed relation 01' contact for carrying out the transfer of nonimmobilized color-providing substances.

In all examples of this specification, percentages of components are given by weight unless otherwise indicated.

Throughout the specification and appended claims, the expression positive image has been used. This expression should not be interpreted in a restrictive sense since it is used primarily for purposes of illustration, in that it defines the image produced on the image-carrying layer as being reversed, in the positive-negative sense, with respect to the image in the photosensitive element. As an example of an alternative meaning for positive image, assume that the photosensitive element is exposed to actinic light through a negative transparency. In this case, the latent image in the photosensitive element will be a positive and the image produced on the image-carrying layer will be a negative. The expression positive image is intended to cover such an image produced on the image-carrying layer.

In the use of certain of the first and second developing agents in accordance with this invention, a temporary stain may be observed on the image-receiving layer. This temporary stain disappears within a short time or may be removed immediately by washing or by swabbing with a slightly acidic solution. It has also been found that incorporating these developing agents in the photosensitive element, e.g., in the emulsion or in a layer behind the emulsion, minimizes or eliminates such temporary staining.

Throughout the specification and claims, the expression superimposing has been used. This expression is intended to cover the arrangement of two layers in overlying relation to each other either in face-to-face contact or in separated condition and including between them at least one layer or stratum of a material which may be a viscous liquid.

Since certain changes may be made in the above processes, products and compositions without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

1 i 7 What is claimed is: 1. A process of forming transfer images in color, comprising developing an exposed silver halide emulsion in the presence of (a) a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye, (b) a 3-pyrazolidone silver halide developing agent and (c) a benzenoid silver halide developing agent, said benzenoid silver halide developing agent containing an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents, oxidizing said dye developer in developed areas of said emulsion as a function of the point-to-point development thereof, whereby an imagewise distribution of unoxidized, diffusible dye developer is provided in undeveloped areas of said emulsion, and transferring, by difiusion, at least a portion of said unoxidized, diffusible dye developer from undeveloped areas to a superposed image-receiving layer to impart thereto a dye image.

2. A process as defined in claim 1, wherein said aryl nucleus of said benzenoid silver halide developing agent is a benzene nucleus.

3. A process as defined in claim 1, wherein said aryl nucleus of said benzenoid silver halide developing agent also contains an alkyl substituent.

4. A process as defined in claim 1, including the step of initiating development by spreading a processing composition between said photosensitive element and said image-receiving layer as said photosensitive element and said image-receiving layer are brought into superposed relationship.

5. A process as defined in claim 1, including the step of separating said photosensitive element from said imagereceiving layer after said transfer of unoxidized, diffusible dye developer has been effected.

6. 'A process as defined in claim 1, wherein one of said substituents of said benzenoid silver halide developing agent is an amino group and said amino group is an alkyl amino group.

7. A process as defined in claim 1, wherein said benzenoid silver halide developing agent is p-benzylaminophenol.

8. A process as defined in claim 1, wherein said benzenoid silver halide developing agent is phenylhydroquinone.

9. A process as defined in claim 1, wherein said dye develop-er contains as the silver halide developing functional group a group selected from the class consisting of para-dihydroxyphenyl, ortho-dihydroxyphenyl, paraaminohydroxyphenyl and ortho-aminohydroxyphenyl groups.

10. A process as defined in claim 1, wherein said dye developer contains as the silver halide developing functional group a para-dihydroxyphenyl group.

11. The process which comprises developing an exposed silver halide emulsion with an aqueous alkaline solution comprising (a) a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye, (b) a 3-pyrazolidone silver halide developing agent and (c) a benzenoid silver halide developing agent, said benzenoid silver halide developing agent con- I taining an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents.

12. A process as defined in claim 11, wherein said 3-pyrazolidone silver halide developing agent is l-phenyl- 3'pyrazolidone and said benzenoid silver halide developing agent is 2,5-bis-ethyleneimino-hydroquinone.

13; A process as defined in claim 11, wherein said i2 3-pyrazolidone silver halide developing agent is l-phenyl- 4,4-dimethyl-3-pyrazolidone.

14. A process as defined in claim 11, wherein said benzenoid silver halide developing agent is Xylohydroquinone.

15. A photographic developer composition comprising an aqueous alkaline solution comprising (a) a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye, (b) a 3-pyrazolidone silver halide developing agent and (c) a benzenoid silver halide developing agent, said benzenoid silver halide developing agent containing an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents.

16. A photosensitive element comprising a plurality of layers, at least one of said layers containing a photosensitive silver halide emulsion; at least one of said layers containing a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye; at least one of said layers containing a B-pyrazolidone silver halide developing agent, and at least one of said layers containing a benzenoid silver halide developing agent, said benzenoid silver halide developing agent containing an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents.

17. A photosensitive element as defined in claim 16, including a plurality of photosensitive silver halide emulsions, each of said emulsions being sensitized to different portions of the spectrum, and each of said emulsions having associated therewith a dye developer of a color substantially complementary to the portion of the visible spectrum to which said emulsion is sensitive.

18. A photosensitive element as defined in claim 17, wherein said silver halide emulsions are superposed on a common support.

19. A photosensitive element as defined in claim 17, wherein said silver halide emulsions are present in the form of minute elements and are arranged in side-by-side relationship in a screen pattern.

20. A photosensitive element as defined in claim 17, wherein said silver halide emulsions include an outermost blue-sensitive emulsion, an inner green-sensitive emulsion and an inner red-sensitive emulsion, said emulsions having associated therewith, respectively, a yellow dye developer, a magenta dye developer and a cyan dye developer.

21 A photographic product which comprises a. photosensitive element comprising a silver halide emulsion; an image-receiving element comprising an image-receiving layer; means interconnecting said photosensitive element for movement relative to said image-receiving element, whereby said photosensitive element is positionable in superposed relation and in relatively close proximity to 831d image-receiving element; a rupturable container holdmg at least a liquid processing composition including a solvent for (a) a dye developer, said dye developer being a compound which is both a silver halide developing agent and a dye, (b) a S-pyrazolidone silver halide developing agent and (c) a benzenoid silver halide developing agent, said benzenoid silver halide developing agent containing an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents, said container being capable of being fractured and of releasing its liquid content between said photosensitive element and said image-receiving element when said elements are brought into superposed relationship; said dye developer, said S-pyrazolidone silver 13 halide developing agent, and said benzenoid silver halide developing agent being positioned in said product; said dye developer being capable of being immobilized in said photosensitive element as a result of the development of said emulsion, thereby providing an imagewise distribution of said dye developer which is not immobilized and which is adapted to be transferred to said superposed image-receiving element and impart a dye image thereto.

22. A photographic product as defined in claim 21, wherein said photosensitive element comprises a bluesensitive silver halide emulsion, a green-sensitive silver halide emulsion and a red-sensitive silver halide emulsion, said emulsions having associated therewith, respectively, a yellow dye developer, a magenta dye developer and a cyan dye developer.

23. A photographic product as defined in claim 22, wherein said silver halide emulsions are superposed on a common support.

24. A photographic product as defined in claim 21, wherein said photosensitive element comprises a plurality of silver halide emulsions in the form of minute elements arranged in side-by-side relationship to provide a screen pattern.

25. A photographic product as defined claim 21,

wherein said 3-pyrazolidone silver halide developing agent and said benzenoid silver halide developing agent are positioned in said rupturable container.

26. A photographic product as defined in claim 21, wherein at least one of (a) said 3-pyrazolidone silver halide developing agent and (b) said benzenoid silver halide developing agent is positioned in said photosensitive element.

27. A photographic product as defined in claim 26, wherein said silver halide developing agent is contained in a layer of said photosensitive element containing said dye developer.

28. A photographic product as defined in claim 21, wherein said S-pyrazolidone silver halide developing agent is 1-phenyl-3-pyrazolidone.

29. A photographic product as defined in claim 21, wherein said 3-pyrazolidone silver halide developing agent is 1-phenyl-4,4-dimethyl-3-pyrazolidone.

30. A photographic product as defined in claim 21, wherein said benzenoid silver halide developing agent is xylohydroquinone.

31. A process of forming multicolor transfer images, comprising exposing a photosensitive element, said photosensitive element comprising a plurality of silver halide emulsions, each of said silver halide emulsions having associated therewith a dye developer, each said dye developer being a compound which is both a silver halide developing agent and a dye, developing said exposed photosensitive element, said development being effected in the presence of a 3-pyrazolidone silver halide developing agent and of a benzenoid silver halide developing agent, said benzenoid silver halide developing agent containing an aryl nucleus substituted by at least two substituents selected from the class consisting of hydroxyl and amino groups, one of said substituents being substituted in one of the ortho and para positions with respect to the other of said substituents, oxidizing each said dye developer as a function of the point-to-point development of the silver halide emulsion with which said dye developer is associated, thereby providing an imagewise distribution of unoxidized dye developer in undeveloped areas of each of said emulsions, and transferring at least a portion of each said imagewise distribution of unoxidized dye developer to a superposed image-receiving layer.

32. A process as defined in claim 31, wherein said photosensitive element contains a blue-sensitive silver halide emulsion, a green-sensitive silver halide emulsion and a red-sensitive silver halide emulsion, said emulsion having associated therewith, respectively, a yellow dye developer, a magenta dye developer and a cyan dye developer.

33. A process as defined in claim 31, wherein said 3-pyrazolidone silver halide developing agent is l-phenyl- 3-pyrazolidone.

34. A process as defined in claim 31, wherein said 3-pyrazolidone silver halide developing agent is l-phenyl- 4,4-dimethyl-3-pyrazolidone.

35. A process as defined in claim 31, wherein said benzenoid silver halide developing agent is 2,5-bisethyleneimino hydroquinone.

36. A process as defined in claim 31, wherein said benzenoid silver halide developing agent is Xylohydroquinone.

References Cited in the file of this patent UNITED STATES PATENTS 2,543,691 Friedman Feb. 27, 1951 2,751,300 James et a1. June 19, 1956 2,756,142 Yutzy July 24, 1956 2,774,668 Rogers Dec. 18, 1956 2,892,710 Cohler et a1. June 30, 1959 OTHER REFERENCES Moss: The Theory of the Photographic Process, page 540, Macmillan Co., Publishers, New York (1954).

Hornsby: Basic Photographic Chemistry, page 37, Foundation Press Publishers, London (1956).

History of Color Photography (1944), Friedman, pages 364-367.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,039,869 June 19, 1962 Howard G. Rogers et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, lines 62 to 67, the formula should appear as shown below instead of as in the patent:

5 0:? c n H-N R column 9, line 65, for "layer" read material Signed and sealed this 7th day of April 1964.

(SEAL) Atlest: EDWARD J. BRENNER ERNEST W. SWIDER Attesting Officer Commissioner of Patents 

31. A PROCESS OF FORMING MULTICOLOR TRANSFER IMAGES, COMPRISING EXPOSING A PHOTOSENSITIVE ELEMENT, SAID PHOTOSENSITIVE ELEMENT COMPRISING A PLURALITY OF SILVER HALIDE EMULSIONS, EACH OF SAID SILVER HALIDE EMULSIONS HAVING ASSOCIATED THEREWITH A DYE DEVELOPER, EACH SAID DYE DEVELOPER BEING A COMPOUND WHICH IS BOTH A SILVER HALIDE DEVELOPING AGENT AND A DYE, DEVELOPING SAID EXPOSED PHOTOSENSITIVE ELEMENT, SAID DEVELOPMENT BEING EFFECTED IN THE PRESENCE OF A 3-PYRAZOLIDONE SILVER HALIDE DEVELOPING AGENT AND OF A BENZENOID SILVER HALIDE DEVELOPING AGENT, SAID BENZENOID SILVER HALIDE DEVELOPING AGENT CONTAINING AN ARYL NUCLEUS SUBSTITUTED BY AT LEAST TWO SUBSTITUENTS SELECTED FROM THE CLASS CONSISTING OF HYDROXYL AND AMINO GROUPS, ONE OF SAID SUBSTITUENTS BEING SUBSTITUTED IN ONE OF THE ORTHO AND PARA POSITIONS WITH RESPECT TO THE OTHER OF SAID SUBSTITUENTS, OXIDIZING EACH SAID DYE DEVELOPER AS A FUNCTION OF THE POINT-TO-POINT DEVELOPMENT OF THE SILVER HALIDE EMULSION WITH WHICH SAID DYE DEVELOPER IS ASSOCIATED, THEREBY PROVIDING AN IMAGEWISE DISTRIBUTION OF UNOXIDIZED DYE DEVELOPER IN UNDEVELOPED AREAS OF EACH OF SAID EMULSIONS, AND TRANSFERRING AT LEAST A PORTION OF EACH SAID IMAGEWISE DISTRIBUTION OF UNOXIDIZED DYE DEVELOPER TO A SUPERPOSED IMAGE-RECEIVING LAYER.
 32. A PROCESS AS DEFINED IN CLAIM 31, WHEREIN SAID PHOTOSENSITIVE ELEMENT CONTAINS A BLUE-SENSITIVE SILVER HALIDE EMULSION, A GREEN-SENSITIVE SILVER HALIDE EMULSION AND A RED-SENSITIVE SILVER HALIDE EMULSION, SAID EMULSION HAVING ASSOCIATED THEREWITH, RESPECTIVELY, A YELLOW DYE DEVELOPER, A MAGENTA DYE DEVELOPER AND A CYAN DYE DEVELOPER. 